Such a locking apparatus for a string of for instance a violin or a guitar is known from U.S. Pat. No. 1,732,172. This known apparatus composes a joint construction with means to tune the individual strings of the stringed instrument. Therefore, the string is guided through an opening in a channel of a tuning means. In order to anchor the string to the stringed instrument the string is subsequently pulled out of the other side of the tuning means. Subsequently, the string is anchored to the locking means. The locking apparatus includes a rotatably arranged locking cam and a locking wall, between which the end of a string can be guided. Both the locking cam and the locking wall in the known apparatus, preferably, include a toughened surface. The locking cam and the locking wall are shaped in such a way, that, when the string is being pulled in the direction of the other end of the string, the locking cam and the locking wall seize and lock the string. Thereby the tensioned string is in direct physical contact with the locking cam over such an extent of the locking cam that the tension of the string provides for a leverage to the rotatably arranged locking cam and increases the locking force of the locking apparatus. In order to use the tuning means, the locking apparatus has to be guided into the channel of the tuning means, while the string remains tensioned. After the string is anchored on its other end, the locking apparatus can be moved through the channel of the tuning means by means of a butterfly nut, in order to regulate the tension in the spring.
In the known locking apparatus the locking cam is not provided with a spring, so that the locking cam, whenever no tensioned spring is inserted, will dangle without taking any defined position. Moreover, when a loose string is guided between the locking cam and the locking wall, the string will not yet be locked. The will only remain locked tight in the locking apparatus when the string is tensioned. By insertion of the string into the locking apparatus in the channel of the tuning means, therefore, the string has to maintain a certain tension, otherwise the string may still slip from the locking apparatus. In case the string as yet slips loose, the whole procedure has to be repeated, which consumes a lot of time. When, for instance during a concert, a string breaks the known apparatus is very unpractical, since changing a string takes a lot of time. This is certainly true, when the string slips loose from the locking apparatus in between. This known apparatus therefore is more suitable for violins, where the strings have a lower tension and are made of a rougher material than strings for a steel string guitar.
The object of the locking apparatus according to the present invention is to solve the problems mentioned above.